Evidence for the acceptability of an injectable hormonal method for men.
Research has been conducted for more than 20 years in both developed and developing countries in the attempt to develop a safe, effective, and reversible hormonal method of contraception for men. A variety of hormonal compounds and contraceptive delivery systems, including injections, pills, implants, and patches, are therefore currently being investigated. Limited funding and a lack of commercial interest in regulating male fertility have, however, slowed progress. It seems that pharmaceutical companies doubt the existence of a market for hormonal contraceptives for men and fear the potential for litigation. Clinical trials, supported by the World Health Organization, of a hormonal method have nonetheless yielded encouraging results. One multicenter study injected men weekly with testosterone enanthate to induce azoospermia. A second study investigated whether the state of complete azoospermia induced by the injections was necessary for contraceptive efficacy. Testosterone enanthate demonstrated its potential application as a hormonal method of contraception for men, but the frequent injections required over the course of 3-4 months to achieve oligozoospermia are impractical. In addition, above normal levels of testosterone result immediately after injection. Testosterone enanthate in future trials will be combined with another hormone to shorten the time needed to achieve a contraceptive effect, or a new formulation which requires less frequent injections and does not produce a physiological peak. A newly formulated product could be ready for introductory trials by 2000. The author presents information from focus group discussions and questionnaires completed by men who volunteered for the trials. Their feedback adds to the limited body of evidence indicating the potential acceptance of a hormonal method of contraception for men.